Tall, trim and and meticulously dressed, his military bearing showing through his gray business suit, Jonathan Schaeffer on Wednesday set out to challenge the government that until very recently he defended.

His table, with a sign that said "Travel With Dignity," was set up in the main concourse at Baltimore-Washington International Marshall Airport. A neat array of material protesting new security measures by the Transportation Security Administration was spread out: a pamphlet Schaeffer wrote describing the TSA's "manual groping of the genitals, breasts and buttocks" as part of the new pat-down; a petition in support of a congressional effort to curtail the TSA; copies of the Constitution; and a "complaint-compliment" form passengers could use to rate their TSA experience.

"We're calling the TSA's bluff on its policies," said Schaeffer, who said he recently left the Navy after six years as a language expert. "This is a nonpartisan issue."

He said his protest at BWI on Wednesday began as a discussion among friends on Facebook.

He got a permit from the airport for his table and set up in a designated spot. Though he knew of no one who planned to protest in the security line, he said he was encouraging people who were asked to go through the scanners to decline.

"But most of the people who are protesting this are choosing not to fly at all," he said.

Schaeffer said he was alarmed by a CBS poll two weeks ago that found 81 percent of the public didn't object to the scanners. A Washington Post-ABC News poll released this week found that nearly two-thirds of Americans support the use of the machines.

"That's a real risk for our civil rights," he said. "It's baffling to me that only 20 percent of the people really care."

"I have my food; I have my water; I expected to stand in line for hours," said Judith Gilbert of Arlington as she arrived more than three hours early for a flight to Connecticut.

Fewer than two dozen people were making their way through security ahead of her, with some being directed to a new scanner but more heading through traditional metal detectors. Seven of the new scanners were in use at BWI, all of the type that uses radio waves rather than radiation.

"I went through the scanner two weeks ago, no problem," Gilbert said. "I believe we need to do the appropriate thing to keep the skies safe. If people have severe objections, they should take the train."

The man in a business suit who greeted Gilbert and ushered her into the lane was Robert G. Seasonwein, the TSA's lawyer at BWI.

"Everybody's walking up and saying 'Where are the crowds? Where is everyone?' " Seasonwein said. "There's about a 20 percent chance of going through the [scanner], and a lot of people are asking for it because it's quicker because the line's usually shorter."

More than 35,000 people passed through security at BWI on Tuesday, and airport spokesman Jonathan O. Dean said a slightly higher number was expected on Wednesday. He said that for all major holiday peak periods, the airport, the TSA and airlines have an "all hands on deck" policy to minimize delays.

Dean said there hadn't been any "opt-out" protests, and he didn't anticipate any, because "the majority of those traveling today bought their tickets months ago," before the movement to protest the new scanners and pat-downs surfaced.

One traveler who didn't care was Adam Trebach, a college student heading home to D.C. who had just stepped off a flight from St. Louis. "I didn't have to go through X-ray or pat-down," he said.

"I think people hear the term 'radiation' and overreact," Trebach said, referring to one type of the new scanners that uses radiation. "The evidence that it does damage is negligible. If it's no more than a cellphone's, then I could care less."

The radiation question, the revealing images produced by the scanners and the pat-downs that make contact with areas that Americans usually don't display on the beach have been the three major objections to TSA's new program.

And for some travelers, fact and fiction have mixed into a stew of confusion.

As Linda Kassab of Ellicot City rode the moving sidewalk toward the BWI parking garage, she turned to Louis Montanino, who had just arrived from Buffalo.

"I heard on the radio that they interviewed a person at Columbia University who said the radiation is a problem and can cause cancer," she said.

"There are two kinds of machines," Montanino replied. "One doesn't use radiation. I just read about it in the newspaper."

According to the TSA, "a person receives more radiation naturally each hour than from one screening."

Brian Gallagher, president of United Way Worldwide, passes through airports frequently and was waiting for his daughter to arrive from St. Louis on Wednesday.

"There's been an overreaction to this," he said. "I travel all the time, and I'd rather have more security than not."

While he sympathized with the privacy concerns some have raised, he said the more important issue is, "Does it work?"

"I've read that it doesn't detect certain plastics and liquids," Gallagher said. "If this whole [controversy] opens up a good debate on how we handle the whole security process, that's healthy."